A long time ago I had a flea problem and I did hire an exterminator and got my cats out for the day. Prior the exterminator I tried DE but it was a pain to vacuum (depends on what type of vacuum cleaner you have) and the DE killed my vacuum! Anyway, after the exterminator did his thing, I bought these traps from Amazon which worked well (I wanted to make sure I had no fleas left).
They come with a light which attracts the fleas and a sticky pad inside. This is sort of like the ones I bought years ago:www.amazon.com/Trapest-Sticky-Dome-Flea-Trap/dp/B00IZ11V5E/ref=sr_1_1?ie=UTF8&qid=1431281309&sr=8-1&keywords=Flea+sticky+trap
I also kept using a flea comb on my cats and had a bowl of soapy water close to me to dip the flea comb in.
Hope this helps,